Radial ball bearings of the type having an inner and outer race with a plurality of bearing balls in rolling engagement therebetween must include a retainer or cage for the balls if less than a full complement of bearing balls is used. While such cages used to be made of metal, it is now preferable to mold such cages as a one piece unit from a plastic material. Such retainers or cages generally include an annular body portion with a plurality of axially opening, spherically concave retention pockets circumferentially spaced therearound, with each retention pocket having a pair of flexible retention lips which flex apart as a ball is inserted therein and flex back to retain the ball. The annular body portion includes an equal number of axially opening gaps between the adjacent ball pockets. During normal Conrad type assembly of the ball bearing, it is desirable to block the bearing balls out of these gaps and also, if possible, to provide side to side separation to guide the bearing balls toward a retention pocket. It is also necessary that the flexibility of the retention lips not be affected.
Ball bearing retainers and cages in the prior art generally include a structure located in the gap between adjacent ball pockets which is either completely separate from the adjacent retention lips or which contains a discontinuity therein, so as to block bearing balls from the gap and provide side to side separation without interfering with the flexibility of the retention lips of the adjacent ball retention pockets. The British patent specification to Bishop et al No. 1,370,890 shows a separate, axially extending projection included in the gap between the retention lips of adjacent ball pockets which blocks bearing balls from the gap during assembly, and, in some embodiments, the projection extends axially beyond the retention lips to provide some side to side guidance of the bearing balls. Since the projection is physically separate from the retention lips, it does not interfere with the flexibility thereof. Similarly, Liss et al U.S. Pat. No. 3,749,461 discloses an axially extending projection in the gap between the retention lips of adjacent ball pockets which extends axially beyond the retention lips and has a conical end to both block balls and provide side to side guidance.
German Pat. No. 1,400,987 to Menninger et al shows a plastic cage with a pair of sloped projections in each gap, one sloping toward a retention lip of each of the adjacent ball pockets. There is a central slot between the projections so that they may flex toward one another with the retention lips. Olschewski et al U.S. Pat. No. 4,278,307 discloses projections in the gaps between the retention lips of adjacent ball pockets, both of the single projection variety and the double projection type, with a deep slit therebetween, and in addition, the projections include deformable axial ends which allow them to be bent over after assembly of the balls to help the retention lips from flexing back to prevent escape of a bearing ball from a ball retention pocket.